1. Field of the Invention
The present invention relates generally to fixtures, tools, and equipment used in the building construction trades, and more specifically to a system for lifting and/or stabilizing foundations, slabs, and the like, of buildings which have settled after construction. The present system includes a lifting bracket with a pipe section which fits concentrically about an anchor pier driven into the ground adjacent the building structure, and precludes any tilting or slippage of the lifting bracket as it lifts the building structure. The present device may be used with either helical or auger type piers which are turned into the ground for anchoring, with xe2x80x9cpushxe2x80x9d type piers or pilings, which are driven straight into the underlying material, or with virtually any other type of piling or pier which might be developed for such work.
2. Description of Related Art
The slow settling of the foundations of buildings, concrete slabs, and other heavy structures is a phenomenon occurring occasionally in various areas, particularly where the underlying soil is not stable. While engineers endeavor to assure that the underlying surface is stable, and/or to construct the foundation of the structure so that it is resting upon a lower layer of stable material, such structures nevertheless will settle on occasion.
As a result, various equipment and techniques have been developed for lifting sunken or settled foundations, slabs, etc. These techniques generally involve the digging of a hole or trench along the structure to be lifted, and driving one or more pipes or piers into the ground adjacent to the structure until the pipes reach stable material or the underlying bedrock. A lifting apparatus is then installed on the support pier and extended beneath a portion of the structure to be raised, and some means (nearly universally hydraulic) is used to lift the lifting apparatus and structure resting thereon. This process is conducted simultaneously every several feet as needed along the length of the structure being raised, in order to distribute the lifting forces generally equally along the structure.
However, such lifting devices as developed in the past, suffer from various deficiencies which can result in considerable additional time and effort on the part of crews engaged in such operations. For example, many of the devices of the prior art are location beneath the edge of a slab or footing. While most such devices include bolts, pins, etc. to secure the lifting device positively to the structure, these are limited in their attachment location and cannot always provide the security desired. Moreover, many of the prior art devices are subject to tilting or cocking angularly when force is applied, thus creating further risk that the lifting device will slip from beneath the foundation or slab.
Another problem incurred using many of the devices of the prior art, is that many such devices do not provide any form of mechanical locking to secure the lifting element (plate, arm, etc.) to its corresponding anchor pier or pipe. The lifting component is raised by one or more hydraulic jacks, but some means must be provided to secure the lifting component to the pier, before the hydraulic devices can be removed. Such assemblies require additional tools in the form of welding equipment, so the lifting element can be welded to its associated anchor pier. This greatly increases the time required for the lifting operation, as well as increasing the expense due to the necessity of providing and transporting welding equipment to the job site.
Accordingly, a need will be seen for an apparatus and method for lifting sunken or settled building foundations, footings, slabs, etc., which provide much more positive support of the overlying building structure than has been the case with devices of the prior art. The present lifting apparatus overcomes this problem by means of a concentric pipe sleeve which passes around the pipe of the anchor pier, thereby precluding any tilting or cocking of the lifting plate. The present device also secures positively to the building structure, with the attachment being adjustably positionable to provide selective attachment to a solid area of the structure.
A discussion of the related art of which the present inventors are aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,982,103 issued on May 2, 1961 to Guy H. Revesz et al., titled xe2x80x9cMethod And Apparatus For Underpinning A Building,xe2x80x9d describes a system with a generally vertically disposed plate which bolts to the wall of the structure being lifted. The Revesz et al. disclosure primarily describes a method of setting the anchor pier into a solid underlying substrate, using the lifting plate bolted to the structure wall and other components. Revesz et al. do not provide any means of supporting the structure from beneath nor of securing the lifting plate directly to the anchor pier, as is done with the present invention. Also, the Revesz et al. lifting plate has four holes in a predetermined pattern. If bolts passing through these holes do not happen to secure to solid material, the entire apparatus must be relocated to an area of solid structural material for secure attachment thereto.
U.S. Pat. No. 3,902,326 issued on Sep. 2, 1975 to George F. Langenbach Jr., titled xe2x80x9cApparatus And Method For Shoring A Foundation,xe2x80x9d describes a system wherein a guide pipe has an elongate hydraulic cylinder installed concentrically therein. The cylinder is secured to a generally C-shaped bracket, which in turn grips one edge of a foundation or footing. The bracket includes a section of pipe which passes around the anchor piling or pier, and is locked thereto by a radially disposed bolt when the lifting operation is complete. However, the Langenbach, Jr. assembly has no provision for attaching the lifting device to the side of the wall, as provided by the present invention, and does not use an externally disposed jack, as is the case with the present system.
U.S. Pat. No. 4,673,315 issued on Jun. 16, 1987 to Robert R. Shaw et al., titled xe2x80x9cApparatus For Raising And Supporting A Building,xe2x80x9d describes a lifting plate including a pipe section which fits around the anchor pipe or pier which is driven into the ground. The plate includes laterally opposed ears or lugs, to which the ends of a pair of hydraulic jacks are secured. The upper ends of the jacks are secured to lugs extending from an adjustably positionable collar on the anchor pier. The jacks are actuated to drive the pier into the ground and eventually raise the structure, when the pier encounters sufficient resistance. However, Shaw et al. fail to provide any means of locking the lifting plate to the anchor pier, other than by welding. Thus, they require welding and metal cutting equipment to secure the lifting plate to the pier, and to remove the section of pipe or pier above the lifting plate. Moreover, Shaw et al. do not provide any means of securing the plate positively to the wall of the structure being lifted.
U.S. Pat. No. 4,695,203 issued on Sep. 22, 1987 to Steven D. Gregory, titled xe2x80x9cMethod And Apparatus For Shoring And Supporting A Building Foundation,xe2x80x9d describes a system functioning similarly to that of the Shaw et al. system described above, but utilizing only a single hydraulic jack centered atop the pier and lifting an inverted saddle, which in turn attaches to the lifting plate or arm by means of a pair of lugs extending therefrom. Again, no mechanical means is provided for securing the lifting plate to the pier pipe. Welding equipment must be provided to weld the assembly together, to allow the hydraulics to be removed.
U.S. Pat. No. 4,708,528 issued on Nov. 24, 1987 to Dondeville M. Rippe, titled xe2x80x9cProcess And Apparatus For Stabilizing Foundations,xe2x80x9d describes a system more closely related to the system described further above in the ""326 U.S. patent to Langenbach, Jr., than to the present invention. Rippe provides a single hydraulic jack which lifts a concentrically placed lifting apparatus above the jack. The lifting apparatus is in turn attached to a concentric lifting cylinder which has a single pin which inserts into a hole formed in the wall of the structure. Thus, the Rippe apparatus does not lift the structure from below, as in the present invention, but relies upon a single pin inserted into a hole in the wall of the structure. The very small bearing cross sectional area provided by the hole in the wall, results in severe limitations insofar as the load which may be supported.
U.S. Pat. No. 4,765,777 issued on Aug. 23, 1988 to Steven D. Gregory, titled xe2x80x9cApparatus And Method For Raising And Supporting A Building,xe2x80x9d describes an apparatus more closely related to those of the ""315 and ""203 U.S. patents respectively to Shaw et al. and Gregory, described further above, than to the present invention. The ""777 Gregory device includes a pair of opposed hydraulic lifting cylinders, which secure to a collar about the upper end of the anchor pier or pipe. The lower ends of the cylinders secure to the lifting bracket. However, the lifting bracket does not have a pipe passing concentrically about the anchor pier, and thus is not as securely held in place as the lifting bracket of the present invention.
U.S. Pat. No. 5,154,539 issued on Oct. 13, 1992 to William B. McCown, Sr. et al., titled xe2x80x9cFoundation Lifting And Stabilizing Apparatus,xe2x80x9d describes an assembly somewhat related to that of the Gregory ""203 U.S. patent described further above. The McCown, Sr. et al. system utilizes a specialized collar disposed above the anchor pier, with a single concentric hydraulic jack attaching to the top of the collar and bearing downwardly against the top of the pier. The jack and collar assembly are retained by a pair of lifting bars which secure to lugs on the collar and to lugs extending from the lifting arm extending beneath the structure being lifted. However, the McCown, Sr. et al. lifting arm does not positively secure to the building structure.
U.S. Pat. No. 5,213,448 issued on May 25, 1993 to Gary L. Seider et al., titled xe2x80x9cUnderpinning Bracket For Uplift And Settlement Loading,xe2x80x9d describes a system utilizing a screw anchor, rather than a pipe pier, for support. Such screw anchors do not provide the bending resistance of a pipe of equal weight, as the columnar strength of a screw anchor is concentrated along its center, rather than being distributed in its walls as in the case of a pipe. Seider et al. respond to this problem by bolting their lifting bracket to the foundation or wall using a plurality of bolts, in an effort to preclude any angular movement of the bracket relative to the wall. However, they do not provide the resistance to relative angular motion between the lifting bracket and its support which is provided by the present invention, due to the open channel of the lifting bracket.
U.S. Pat. No. 5,492,437 issued on Feb. 20, 1996 to Leo P. Ortiz, titled xe2x80x9cSelf-Aligning Devices And Methods For Lifting And Securing Structures,xe2x80x9d describes a system more closely related to that of the ""315 and ""777 U.S. patents respectively to Shaw and Gregory, discussed further above, than to the present invention. Ortiz uses two opposed hydraulic cylinders, but secures them to a pivot at the top of the anchor pier in order to compensate for slight irregularities in the forces involved. Otherwise, the Ortiz device is quite similar to other systems utilizing two opposed hydraulic cylinders. The Ortiz assembly cannot be progressively secured in place, as provided by the present invention. Rather, holes are drilled into the anchor pier through existing holes formed in the surrounding pipe of the lifting bracket, and the lifting bracket is bolted in place at the end of the operation.
U.S. Pat. No. 5,724,781 issued on Mar. 10, 1998 to Billie H. Matthias et al., titled xe2x80x9cMethod For Raising Foundations,xe2x80x9d describes an apparatus more closely resembling that of the Gregory ""203 U.S. patent discussed further above, than the present system. Matthias et al. place a hydraulic cylinder atop the pier and use it to lift an inverted saddle extending across the top of the lifting cylinder, to lift the lifting bracket by ears or lugs extending therefrom. While FIGS. 4 and 5 of Matthias et al. appear to show threaded lifting rods, they are not described as such, and in any event, no disclosure is made of stop nuts beneath the plate to hold the assembly at some intermediate position, nor is any provision made for positively securing the lifting bracket to the structure.
British Patent Publication No. 325,093 accepted on Feb. 13, 1930 to Julian A. Formunt, titled xe2x80x9cImprovements Relating To The Provision Of Substructures, Particularly For Subaqueous Work,xe2x80x9d describes a system for supporting a structure constructed on the bottom of a body of water, as in a bridge pier or the like. A caisson is placed adjacent the base of the structure and into the underlying substrate. The material underlying the structure is then removed and the caisson is moved progressively laterally into position beneath the structure, with pilings or other supports being progressively removed and replaced as required for movement of the caisson. The Formunt system does not provide any means for lifting the overlying structure, but only for supporting it by installing a series of pilings, with the caisson being required during the operation.
British Patent Publication No. 985,351 published on Mar. 10, 1965 to Ludwig Muller, titled xe2x80x9cMethod Of And Means For Underpinning A Building,xe2x80x9d describes a system wherein pairs of hydraulic rams are placed beneath a structure, with a girder extending thereacross. The rams are actuated to drive the girder downwardly, whereupon it presses a piling into the substrate. A column is constructed atop the driven piling to support the overlying building structure, once the girder has been removed. The Muller system is relatively more cumbersome than the present building lifting system, in that it requires the extra step of constructing a column atop the piling, once it has been driven.
Finally, British Patent Publication No. 1,418,164 published on Dec. 17, 1975 to Pynford Limited, titled xe2x80x9cImprovements In Under-Pinning,xe2x80x9d describes a system wherein a series of relatively small diameter piers is sunk into the ground adjacent or beneath the edge of the structure to be lifted. A concrete cap is then poured around the upper ends of the pier cluster, to support the overlying building structure. In one embodiment, a plate is bolted to the side of a foundation support beam during the operation; no underlying support plate is provided. In any event, the plate is removed after the concrete support pad has been poured and cured.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
An apparatus for lifting sunken or settled foundations, footings, and other base structures of buildings and the like, includes a lifting plate which is welded or otherwise solidly attached to a section of pipe which passes through a hole in the plate. The pipe in turn fits concentrically around the anchor pier or pipe, which is driven into the underlying surface. The pipe section of the anchor plate precludes the cocking or misalignment of the lifting plate as it is being raised, thus providing a much more secure operation, with only a single foundation attachment fitting being required.
The foundation attachment fitting generally comprises a separate clamp which passes around the pipe section of the lifting plate. This clamp may be placed adjustably at any point along the length of the lifting plate pipe, thus allowing the worker to adjust the position of the attachment of the clamp to the foundation structure as required in order to provide solid attachment points for the clamp. No other attachment is required for the lifting plate to the foundation structure.
The present invention also includes a method of lifting a sunken or settled building structure or the like, in which at least one anchor pier is driven into the underlying surface, the lifting plate is placed thereon by sliding the pipe fitting of the plate over the anchor pier pipe, and the lifting plate to foundation attachment clamp is secured to the foundation at a selected solid area of the foundation. A single portable hydraulic jack (e. g., bottle jack) is placed atop a plate on the anchor pier to lift an overlying crossmember which is in turn attached to the lifting plate by an opposed pair of threaded lifting or tension members. After the foundation has been raised as required, the anchor pier plate is immovably secured to the lifting plate by the laterally opposed tension members, and the overlying crossmember and hydraulic jack are removed. The present apparatus and method provide an extremely secure means of lifting and/or stabilizing sunken or settled foundation areas, without the additional labor required to set a series of attachment bolts and the expense involved in multiple lifting jacks or rams. The present foundation lifting apparatus may be used with virtually any type of piling or pier desired, e.g., helical piers using the auger principle, push type piers, etc., as desired.
Accordingly, it is a principal object of the invention to provide an apparatus for lifting and/or stabilizing sunken or settled foundations, footings, and the like, of building structures, which apparatus includes a lifting plate having a pipe section solidly attached thereto, with the pipe section passing around the anchor pier for precluding cocking or tilting of the lifting plate relative to the foundation structure during the lifting operation.
It is another object of the invention to provide an apparatus for lifting sunken foundations including a single clamp to secure the lifting plate to the foundation, the clamp being selectively positionable by a worker for placement at a location on the foundation which provides a solid attachment point for the clamp.
It is a further object of the invention to provide an apparatus for lifting sunken foundations which secures the lifting plate in position on the anchor pier by mechanical means, precluding any further requirement for welding or other metal working or forming equipment.
Still another object of the invention is to provide a method of lifting the sunken or settled foundation of a building structure, utilizing the above described apparatus.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become apparent upon review of the following specification and drawings.